Wave guide for high-frequency electric currents



June 20, 1950 D. T. HOLLINGSWORTH Ef AL 2,511,916

WAVE GUIDE FOR HIGH-FREQUENCY ELECTRIC CURRENTS Filed June 16 1945 FIG. I

1: PW E FABRIC E FIG. 2 I

: -VULCANIZED RUBBER Attorney Patented June 20, 1950 ,WAYE

land

Application June 16, 1945, Se In Great Britain July 6, 19

3 Claims.

This invention relates to wave guides for high frequency electric currents of the kind in which the guid is a tube of rectangular cross section with a conductive inner surface layer. The object of the invention is to provide a length of such a guide which has sufficient flexibility combined with a minimum distortion of cross section to ermit it to undergo bending and/or twisting within desired limits, without great loss of electrical efficiency. Such a length may, for instance, be required for connection between two lengths of rigid guide on two parts of a structure between which relative movement can take place from time to time.

The improved guide is made as a tube of wire fabric of fine mesh which is accurately shaped to enclose a rectangle of the required dimensions and is held yieldingly in this form by an external covering of vulcanised rubber (or other equivalent material.) This material is preferably moulded on to the tube and vulcanised (or otherwise toughened) in position.

To give the required flexibility, both in bending and twisting, the rubber-backed woven wire fabric is, in accordance with the invention, made in such a manner that neither of the two interwoven sets of wires run in lines which make, with a plane containing the axis and normal to the wall of the tube, an angle either in the neighbourhood of or of 45.

A longitudinal section of a length of a wave guide made in accordance with the invention is shown, by way of example, in Figure 1 of the accompanying drawing. Figures 2 and 3 show in conventional manner two kinds of wire fabric. In this example the rectangular tube of wire fabric I is formed from a sheet of fabric bent over a former and closed by a seam indicated by the broken line 2. This tube is joined by means of short tubes 3 of thin metal to connecting members 4 and 5 by which this flexible part of the guide is joined to the adjacent fixed parts, The tube 1 is yieldingly supported by a covering 6 of vulcanised rubber. This covering is moulded on to the tube while the tube is mounted on its former and the covering is then vulcanised. A trace of a plane of reference is shown by the line 1--'!.

The fabric used may be produced either by weaving (Figure 2) or braiding (Figure 3), In either case there are two sets of wires interlaced. If these wires cross each other at right angles then, in accordance with the invention, one set of them makes an angle with the plane of reference above mentioned, which is in the range 50 2511mm GUIDE-EOE HIG I. 3 3 T? ER -N1 Douglas Taft Hollingswortm London, And William James Morley, Malvern Common, Eng

grammar...

to 80, while the other set makes an angle which lies within the range 40 to 10. Preferable values of the two angles are and 30 as shown in Figure 2.

If the fabric is manufactured with two sets of wires crossing at an angle other than 90, as indicated in the example shown in Figures 1 and 3, then it is possible, and advantageous, to have both sets of wires making an angle with the plane of reference greater than 45. They can then make angles which lie within the range 50 to In the example they both make angles of 60.

With the composite fabric described the selection of the values above indicated assists in the obtaining of uniformity of flexibility with a minimum of distortion of the cross section.

It is to be understood that the term rubber used herein is not to be limited to natural rubber. Its function is to provide a covering and binding for the tube and the ribs which gives a strong but yielding support to the tube of gauze and which can be moulded thereon. In addition to natural rubber various synthetic rubbers and rubber-like materials having the required properties may be used. They may be capable of application in the cold followed by hardening and toughening by a heat treatment analagous to vulcanisation in its effect, or they may be thermoplastic and applied hot regaining their toughness and comparative hardness on cooling.

What we claim as our invention is:

1. A wave guide for high frequency electric currents, said wave guide being of rectangular internal cross section and comprising a hollow tube of fine mesh wire fabric consisting of two sets of parallel wires interwoven and a covering of rubber tightly fitting on said tube and holding it yieldingly in shape, the interior of said hollow tube containing only gas, the fabric of said tube having its two interwoven sets of wires running in lines which make with a plane containing the axis and normal to the wall of the tube an angle which differs by at least 5 from 0 and from 45.

2. A wave guide for high frequency electric currents, said wave guide being of rectangular internal cross section and comprising a hollow tube of fine mesh wire fabric consisting of two sets of parallel wires interwoven formed of two sets of wires which run at right angles to each other and are interwoven, and a covering of rubber tightly fitting on said tube and holding it yieldingly in shape, the interior of said hollow tube containing only gas, one of said sets of wires making with a plane containing the axis and nor- 3 mal to the wall or the tube an angle which lies in the range 50 to 80.

3. A wave guide for high frequency electric currents, said wave guide being of rectangular internal cross section and comprising a hollow tube of fine mesh wire fabric consisting of two sets of parallel wires interwoven and a covering of rub-' ber fitting tightly on said tube and holding it yieldingly in shape, the interior of said hollow,

tube containing only gas, said fabric having two interwoven sets of wires which run in lines which make with a plane containing the axis and normal to the wall of the tube an angle which lies in the range 50 to 80.

DOUGLAS TAFI' HOLLINGSWORTI-I. CYRIL WILLIAM JAMES MORLEY.

4 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PA'IEN'TS Number Name a Date 2,113,735 Ma'scuch Apr. 12, 1938 2,287,134 Robertson June 23, 1942 2,342,736 Herzog Feb. 29, 1944 2,416,177 Hollingsworth Feb. 18, 1947 2,436,421 Cork Feb. 24, 1948 2,479,288 Allen Aug. 16, 1949 

